EN
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The new iPWER™ high performance 20 A SSQL48T20033 DC-DC converter
provides a high efficiency single output, in a 1/16th brick package that is only
56% the size of the industry-standard eighth-brick. Specifically designed for
operation in systems that have limited airflow and increased ambient
temperatures, the SSQL48T20033 converter utilizes the same pin-out and
Input / Output functionality of the industry-standard sixteenth-bricks. In
addition, a heat spreader feature is available (-xxxBx suffix) that provides an
effective thermal interface for coldplate and heat sinking options.
The SSQL48T20033 converter thermal performance is accomplished through
the use of patent-pending circuits, packaging, and processing techniques to
achieve ultra-high efficiency, excellent thermal management, and a low body
profile.
Low-body profile and the preclusion of heat sinks minimize impedance to
system airflow, thus enhancing cooling for both upstream and downstream
devices. The use of 100% automation for assembly, coupled with advanced
electronic circuits and thermal design, results in a product with extremely high
reliability.
Operating from a wide-range 36-75 V input, the SSQL48T20033 converter
provides a fully regulated 3.3 V output voltage. The outputs can be trimmed
from –20% to +10% of the nominal output voltage, thus providing outstanding
design flexibility. Employing a standard power pin-out, the SSQL48T20033
converter is an ideal drop-in replacement for existing high current eighth-brick
designs. Inclusion of this converter in a new design can result in significant
board space and cost savings. The designer can expect reliability
improvement over other available converters because of the SSQL48T20033’s
optimized thermal efficiency.
36-75 VDC Input; 3.3 VDC @ 20 A
Industry-standard eighth-brick pin-out
Withstands 100 V input transient for 100 ms
Fixed-frequency operation
On-board input differential LC-filter
Start-up into pre-biased load
No minimum load required
Hiccup overcurrent protection
Fully protected (OTP, OCP, OVP, UVLO)
Remote sense
High efficiency – no heat sink required (Baseplate/heat spreader option
(suffix ‘-xxxBx’) facilitates heatsink mounting to further enhance the unit’s
thermal capability.)
Remote ON/OFF positive or negative logic option
Output voltage trim range: +10%/−20% with industry-standard trim equations
Designed to meet Class B conducted emissions per FCC and EN55022 when
used with external filter
All materials meet UL94, V-0 flammability rating
Approved to the latest edition and amendment of ITE Safety standards, UL/CSA
60950-1 and IEC60950-1
RoHS lead free solder and lead-solder-exempted products are available
SSQL48T20033
2
Conditions: TA = 25ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.
PARAMETER
CONDITIONS / DESCRIPTION
MIN
Continuous
-0.3
TYP
MAX
UNITS
Absolute Maximum Ratings
Input Voltage
Transient (100ms)
Operating Temperature 1
(See Derating Curves)
VDC
VDC
Ambient (TA)
-40
85
°C
Component (TC)
-40
120
°C
Baseplate (TB)
-40
105
°C
-55
125
°C
FE
Storage Temperature
Isolation Characteristics
I/O Isolation
2,250
Isolation Capacitance
150
Isolation Resistance
Output to Baseplate
Feature Characteristics
Switching Frequency
Industry-std. equations3
2, 4
1,500
VDC
1,500
VDC
F
Non-latching
Turn-On Time from Vin
Turn-On Time from ON/OFF Control
115
kHz
+10
%
+10
%
140
%
125
°C
200
ms
O
Non-latching
Over Temperature Shutdown
Auto-Restart Period
-20
Percent of VOUT(NOM)
Output Overvoltage Protection
pF
MΩ
500
Output Voltage Trim Range 2
VDC
10
LI
Input to Baseplate
Remote Sense Compensation
80
100
Converter Off (logic low)
-20
0.8
VDC
Converter On (logic high)
2.4
20
VDC
Applies to all protection features
Time from UVLO to Vo = 90%VOUT(NOM)
Resistive Load
Time from ON to Vo = 90%VOUT(NOM)
Resistive Load
4
20
ms
4
20
ms
EN
D
ON/OFF Control (Positive Logic option)
Converter Off (logic high)
2.4
20
VDC
Converter On (logic low)
-20
0.8
VDC
36
48
75
VDC
Turn-on Threshold
31.5
33.5
35.5
VDC
Turn-off Threshold
30
32
34
VDC
2.0
VDC
ON/OFF Control (Negative Logic option)
Input Characteristics
Operating Input Voltage Range
Input Undervoltage Lockout
Lockout Hysteresis Voltage
Maximum Input Current
3.3 Vout, Full Load @ 36 VDC In
Input Standby Current
Vin = 48 V, converter disabled
1.0
2.1
5
ADC
mADC
1
Reference Figure H for component (TC and TB) locations.
Vout can be increased up to 10% via the sense leads or up to 10% via the trim function. However, the total output voltage trim-up
should not exceed 10% of VOUT(NOM).
3
Trim equations are defined within this document’s “Operations” section.
4
When using remote sense a minimum of 100uF ceramic capacitance should be mounted between Vout(+) and Vout(-) close to pin 8
and pin 4.
2
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SSQL48T20033
3
Input No Load Current
(No load on the output)
Vin = 48 V, converter enabled
Input Reflected-Ripple Current, ic
45
65
mADC
100
200
mAPK-PK
Vin = 48 V, 20 MHz bandwidth,
Full Load (resistive) (See Fig. J)
Input Reflected-Ripple Current, iS
Input Voltage Ripple Rejection
@ 120 Hz
150
mARMS
30
mAPK-PK
5
mARMS
60
dB
Output Characteristics
VIN = 48 V, IOUT = 0 Amps, TA = 25°C
Output Regulation
3.3
3.35
VDC
Over Line
IOUT = 20 Amps, TA = 25°C
±2
±17
mV
Over Load
VIN = 48 V, , TA = 25°C
±2
±17
mV
3.4
VDC
30
100
mVPK-PK
Output Voltage Range
Over line, load and temperature
Output Ripple and Noise – 20 MHz
bandwidth
Plus Full Load (resistive)
Output Current Range
Current Limit Inception
Short-Circuit Current
Non-latching
30
VRMS
0
1
10,000
µF
mOhm
0
20
ADC
22
Pk:
RMS:
15
CEXT
ESR
LI
External Load Capacitance
3.2
IOUT = 20 Amps,
CEXT =10 µF tantalum + 1 µF ceramic
5
3.25
FE
Output Voltage Setpoint
Non-latching Short = 10 mΩ
26
30
ADC
35
Amps
8
ARMS
±50
mV
±100
mV
50
µs
89
90.5
%
90
91.0
%
Dynamic Response
Efficiency
@ 100% Load
@ 50% Load
Environmental Characteristics
F
Settling Time to 1% of VOUT
O
Load Change 50%-75%-50% of IOUT Max
di/dt = 0.1 A/μs
CEXT = 10µF tantalum + 1µF ceramic
di/dt = 1.0 A/μs
CEXT = 470µF POS + 1µF ceramic
48 VIN, TA = 25°C, 300 LFM (1.5 m/s)
RH (Non-condensing)
95
%
Storage Humidity
RH (Non-condensing)
95
%
EN
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Operating Humidity
Mechanical Characteristics
Dimensions
No Baseplate
Weight
With Baseplate
14.1
g
23 ± 1
g
23
MHrs
Reliability
Telcordia SR-332, Method I Case 1 50%
electrical stress, 40°C components
MTBF
EMI and Regulatory Compliance
Conducted Emissions
CISPR 22 B with external EMI filter network
Safely Agency Approvals
UL60950-1/CSA60950-1, EN60950-1 and
IEC60950-1
5
See “Input Output Impedance”, Page 4.
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SSQL48T20033
4
FE
These power converters have been designed to be stable with no external capacitors when used in low inductance input and
output circuits.
In many applications, the inductance associated with the distribution from the power source to the input of the converter can
affect the stability of the converter. The addition of a 33 μF electrolytic capacitor with an ESR 1mΩ.
The ON/OFF pin is used to turn the power converter on or off remotely via a system signal. There are two remote control
options available, positive and negative logic, with both referenced to Vin(-). A typical connection is shown in Fig. A.
SSQL 48 Converter
Vin (+)
(Top View )
TRIM
Rload
LI
ON /OFF
Vin
Vout (+)
SENSE (+)
SENSE (-)
Vin ( -)
CONTROL
INPUT
Vout (-)
Figure A. Circuit configuration for ON/OFF function.
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The positive logic version turns on when the ON/OFF pin is at logic high and turns off when at logic low. The converter is on
when the ON/OFF pin is left open. See the Electrical Specifications for logic high/low definitions.
The negative logic version turns on when the pin is at logic low and turns off when the pin is at logic high. The ON/OFF pin
can be hard wired directly to Vin(-) to enable automatic power up of the converter without the need of an external control
signal.
The ON/OFF pin is internally pulled up to 5 VDC through a resistor. A properly de-bounced mechanical switch, open-collector
transistor, or FET can be used to drive the input of the ON/OFF pin. The device must be capable of sinking up to 0.2 mA at a
low level voltage of ≤ 0.8 V. An external voltage source (±20 V maximum) may be connected directly to the ON/OFF input, in
which case it must be capable of sourcing or sinking up to 1 mA depending on the signal polarity. See the Startup Information
section for system timing waveforms associated with use of the ON/OFF pin.
The remote sense feature of the converter compensates for voltage drops occurring between the output pins of the
converter and the load. The SENSE(-) (Pin 5) and SENSE(+) ( Pin 7) pins should be connected at the load or at the point
where regulation is required (see Fig. B). When using remote sense a minimum of 100uF ceramic capacitance should be
mounted between Vout(+) and Vout(-) close to the pin 8 and pin 4.
Vin
Vin (+)
SSQL 48 Converter
Vout (+)
(Top View )
Rw
100
SENSE (+)
ON /OFF
TRIM
SENSE
(-)
10
Vin (- )
Vout ( -)
Rw
Figure B. Remote sense circuit configuration.
CAUTION
If remote sensing is not utilized, the SENSE(-) pin must be connected to the Vout(-) pin, and the SENSE(+) pin must be
connected to the Vout(+) pin to ensure the converter will regulate at the specified output voltage. If these connections
are not made, the converter will deliver an output voltage that is slightly higher than the specified data sheet value.
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SSQL48T20033
5
FE
Because the sense leads carry minimal current, large traces on the end-user board are not required. However, sense traces
should be run side by side and located close to a ground plane to minimize system noise and ensure optimum performance.
The converter’s output overvoltage protection (OVP) circuitry senses the voltage across Vout(+) and Vout(-), and not across
the sense lines, so the resistance (and resulting voltage drop) between the output pins of the converter and the load should
be minimized to prevent unwanted triggering of the OVP.
When utilizing the remote sense feature, care must be taken not to exceed the maximum allowable output power capability
of the converter, which is equal to the product of the nominal output voltage and the allowable output current for the
given conditions.
When using remote sense, the output voltage at the converter can be increased by as much as 10% above the nominal rating
in order to maintain the required voltage across the load. Therefore, the designer must, if necessary, decrease the maximum
current (originally obtained from the derating curves) by the same percentage to ensure the converter’s actual output power
remains at or below the maximum allowable output power.
RTINCR
LI
The output voltage can be adjusted up 10% or down 20% relative to the rated output voltage by the addition of an externally
connected resistor. For output voltage 3.3 V, trim up to 10% is guaranteed only at Vin ≥ 40V, and it is marginal (8% to 10%)
at Vin = 36 V.
The TRIM pin should be left open if trimming is not being used. To minimize noise pickup, a 0.1 μF capacitor is connected
internally between the TRIM and SENSE(-) pins.
To increase the output voltage (Fig. C) a trim resistor, RT-INCR, should be connected between the TRIM (Pin 6) and SENSE(+)
(Pin 7), with a value of:
5.11(100 Δ)V ONOM 626
10.22
1.225Δ
, [kΩ],
where,
F
RTINCR Required value of trim-up resistor [kΩ]
VONOM Nominal value of output voltage [V]
VOREQ
(VO-REQ VO-NOM )
X 100
VO -NOM
O
Δ
, [%]
Desired (trimmed) output voltage [V].
EN
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When trimming up, care must be taken not to exceed the converter‘s maximum allowable output power. See the previous
section for a complete discussion of this requirement.
Vin
Vin (+)
SSQL 48 Converter
Vout (+)
(Top View )
SENSE (+)
ON /OFF
R T - INCR
TRIM
Rload
SENSE (-)
Vin (-)
Vout (-)
Figure C. Configuration for increasing output voltage.
To decrease the output voltage (Fig. D), a trim resistor, RT-DECR, should be connected between the TRIM (Pin 6) and SENSE(-) (Pin
5), with a value of:
RTDECR
511
10.22
|Δ|
[kΩ]
where,
RTDECR Required value of trim-down resistor [kΩ]
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6
and
Δ
is defined above.
Note:
The above equations for calculation of trim resistor values match those typically used in conventional industry-standard
quarter-bricks, eighth-bricks and sixteenth-bricks.
Vin (+)
SSQL 48 Converter
(Top View )
ON /OFF
Vin
Vout (+)
SENSE (+)
TRIM
Rload
R T -DECR
SENSE ( -)
Vout (-)
FE
Vin (-)
Figure D. Configuration for decreasing output voltage.
LI
Trimming/sensing beyond 110% of the rated output voltage is not an acceptable design practice, as this condition could
cause unwanted triggering of the output overvoltage protection (OVP) circuit. The designer should ensure that the difference
between the voltages across the converter’s output pins and its sense pins does not exceed 10% of VOUT(nom), or:
[VOUT() VOUT()] [VSENSE() VSENSE()] VO - NOM X 10% [V]
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This equation is applicable for any condition of output sensing and/or output trim.
EN
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Input undervoltage lockout is standard with this converter. The converter will shut down when the input voltage drops below
a pre-determined voltage.
The input voltage must be typically above 34 V for the converter to turn on. Once the converter has been turned on, it will shut
off when the input voltage drops typically below 32 V. This feature is beneficial in preventing deep discharging of batteries
used in telecom applications.
All output circuit protection features are non-latching and operate in a “hiccup” mode. After an output protection event occurs,
the converter will be turned off, and held off for approximately 200 ms after which, the protection circuit will reset and the
converter will attempt to restart. If the fault is still present, the converter will repeat the above action. Once the fault is removed,
the converter will start normally.
The converter is protected against overload or short circuit conditions. Upon sensing an overload condition, the converter
enters constant current mode of operation and will shut down if overload condition is longer than 10 msec.
Once this occurs, it will enter hiccup mode and attempt to restart approximately every 200 ms with an approximate duty cycle
of 9%. The attempted restart will continue indefinitely until the overload or short circuit condition is removed. Once the output
current is brought back into its specified range, the converter automatically exits the hiccup mode and resumes normal
operation.
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SSQL48T20033
7
The converter will shut down if the output voltage across Vout(+) and Vout(-) exceeds the threshold of the OVP circuitry. The
OVP circuitry contains its own reference, independent of the output voltage regulation loop. Once the converter has shut
down, it will attempt to restart every 200 ms until the OVP condition is removed.
FE
The converter will shut down under an overtemperature condition to protect itself from overheating caused by operation
outside the thermal derating curves, or operation in abnormal conditions such as system fan failure. The converter will
automatically restart after it has cooled to a safe operating temperature.
LI
The converters are safety approved to UL/CSA60950-1, EN60950-1, and IEC60950-1. Basic Insulation is provided between
input and output.
The converters have no internal fuse. To comply with safety agencies requirements, an input line fuse must be used external
to the converter. A 5 A fuse is recommended for use with this product. The SSQL48T20033 converter is UL approved for a
maximum fuse rating of 15 A.
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F
EMC requirements must be met at the end-product system level, as no specific standards dedicated to EMC characteristics
of board mounted component DC-DC converters exist. However, Bel Power Solutions tests its converters to several system
level standards, primary of which is the more stringent EN55022, Information technology equipment - Radio disturbance
characteristics - Limits and methods of measurement.
An effective internal LC differential filter significantly reduces input reflected ripple current, and improves EMC.
With the addition of a simple external filter, the SSQL48T20033 converter will pass the requirements of Class B conducted
emissions per EN55022 and FCC requirements. Refer to Figures 17 – 18 for typical performance with external filter.
VIN
EN
D
Scenario #1: Initial Startup From Bulk Supply
ON/OFF function enabled, converter started via application of
VIN. See Figure E.
Time
t0
Comments
ON/OFF pin is ON; system front-end power is
toggled on, VIN to converter begins to rise.
t1
VIN crosses undervoltage Lockout protection circuit
threshold; converter enabled.
t2
Converter begins to respond to turn-on command
(converter turn-on delay).
t3
Converter VOUT reaches 100% of nominal value.
For this example, the total converter startup time (t3- t1) is
typically 4 ms.
ON/OFF
STATE
OFF
ON
VOUT
t0
t1 t2
t
t3
Figure E. Startup scenario #1.
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8
VIN
Scenario #2: Initial Startup Using ON/OFF Pin
With VIN previously powered, converter started via ON/OFF pin.
See Figure F.
Comments
t0
VINPUT at nominal value.
t1
Arbitrary time when ON/OFF pin is enabled
(converter enabled).
End of converter turn-on delay.
Converter VOUT reaches 100% of nominal value.
t2
t3
ON/OFF
STATE OFF
ON
For this example, the total converter startup time (t3- t1) is
typically 4 ms.
VOUT
FE
Time
t0
t1 t2
t3
t
Figure F. Startup scenario #2.
Comments
VIN and VOUT are at nominal values; ON/OFF pin ON.
ON/OFF pin arbitrarily disabled; converter output
falls to zero; turn-on inhibit delay period (200 ms
typical) is initiated, and ON/OFF pin action is
internally inhibited.
t2
ON/OFF pin is externally re-enabled.
If (t2- t1) ≤ 200 ms, external action of ON/OFF
pin is locked out by startup inhibit timer.
If (t2- t1) > 200 ms, ON/OFF pin action is
internally enabled.
t3
Turn-on inhibit delay period ends. If ON/OFF pin is
ON, converter begins turn-on; if off, converter awaits
ON/OFF pin ON signal; see Figure F.
t4
End of converter turn-on delay.
t5
Converter VOUT reaches 100% of nominal value.
For the condition, (t2- t1) ≤ 200 ms, the total converter startup
time (t5- t2) is typically 204 ms. For (t2- t1) > 200 ms, startup will
be typically 4 ms after release of ON/OFF pin.
ON/OFF
STATE
200 ms
OFF
ON
V OUT
t0
t1
t2
t3 t4
t5
t
Figure G. Startup scenario #3.
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Time
t0
t1
V IN
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Scenario #3: Turn-off and Restart Using ON/OFF Pin
With VIN previously powered, converter is disabled and then
enabled via ON/OFF pin. See Figure G.
The converter has been characterized for many operational aspects, to include thermal derating (maximum load current as
a function of ambient temperature and airflow), efficiency, startup and shutdown parameters, output ripple and noise,
transient response to load step-change, overcurrent, and short circuit.
The following pages contain specific plots or waveforms associated with the converter. Additional comments for specific
data are provided below.
All data presented were taken with the converter soldered to a test board, specifically a 0.060” thick printed wiring board
(PWB) with four layers. The top and bottom layers were not metalized. The two inner layers, comprised of two-ounce copper,
were used to provide traces for connectivity to the converter.
The lack of metallization on the outer layers as well as the limited thermal connection ensured that heat transfer from the
converter to the PWB was minimized. This provides a worst-case but consistent scenario for thermal derating purposes.
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SSQL48T20033
9
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FE
All measurements requiring airflow were made in the vertical and/or horizontal wind tunnel using Infrared(IR) thermography
and thermocouples for thermometry.
Ensuring components on the converter do not exceed their ratings is important to maintaining high reliability. If one
anticipates operating the converter at or close to the maximum loads specified in the derating curves, it is prudent to check
actual operating temperatures in the application. Thermographic imaging is preferable; if this capability is not available, then
thermocouples may be used. The use of AWG #36 gauge thermocouples is recommended to ensure measurement accuracy.
Careful routing of the thermocouple leads will further minimize measurement error. Refer to Figure H for the optimum
measuring thermocouple location.
Fig. H: Location of the thermocouple for thermal testing.
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AIR COOLED
Load current vs. ambient temperature and airflow rates are given in Figures 1 - 3. Ambient temperature was varied between
25°C and 85°C, with airflow rates from 30 to 500LFM (0.15 to 2.5m/s).
For each set of conditions, the maximum load current was defined as the lowest of:
(i) The output current at which any FET junction temperature does not exceed maximum temperature of 120°C as
indicated by the thermal measurement, or
(ii) The output current at which the temperature at the thermocouple locations TC1 and TC2 do not exceed 105°C and
120°C, respectively (Fig. H).
(iii) The nominal rating of the converter (20A).
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BASEPLATE/COLDPLATE COOLING
The maximum load current rating vs. baseplate temperature is provided in Figure 4. The baseplate temperature (TB) was
maintained ≤ 105°C, with an airflow rate of ≤ 30 LFM (≤ 0.15 m/s) and ambient temperature ≤ 85°C. Thermocouple
measurements (in Fig. H) were recorded with TC2 ≤ 120°C. The user should design for TB ≤ 105°C.
Efficiency vs. load current is showing in Figure 5 for ambient temperature (TA) of 25ºC, airflow rate of 300 LFM (1.5m/s) with
vertical mounting and input voltages of 36 V, 48 V, 65 V and 75 V. Also, a plot of efficiency vs. load current, as a function of
ambient temperature with Vin = 48 V, airflow rate of 200 LFM (1 m/s) with vertical mounting is shown in Figure. 6.
Power dissipation vs. load current is showing in Figure 7 for TA = 25ºC, airflow rate of 300LFM (1.5m/s) with vertical mounting
and input voltages of 36 V, 48 V, 65 V and 75 V. Also, a plot of power dissipation vs. load current, as a function of ambient
temperature with Vin = 48 V, airflow rate of 200 LFM (1m/s) with vertical mounting is shown in Figure. 8
Output voltage waveforms, during the turn-on transient using the ON/OFF pin for full rated load currents (resistive load) are
shown with and without external load capacitance in Figure 9 and Figure 10.
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Figure 13 shows the output voltage ripple waveform, measured at full rated load current with a 10 μF tantalum and a 1 μF
ceramic capacitor across the output. Note that all output voltage waveforms are measured across the 1μF ceramic capacitor.
The input reflected-ripple current waveforms are obtained using the test setup shown in Fig. J. The corresponding waveforms
are shown in Figure 14, and Figure 15.
iC
10 µH
source
inductance
V source
1 µF
Ceramic
+ 10 µF
Tantalum
Capacitor
SSQL 48
33 µF
ESR < 1 Ω
electrolytic
capacitor
DC -DC
Converter
Vout
FE
iS
Fig. J: Test setup for measuring input reflected ripple currents, ic and is.
25
LI
25
20
20
15
15
500 LFM (2.5 m/s )
400 LFM (2.0 m/s )
300 LFM (1.5 m/s )
200 LFM (1.0 m/s )
100 LFM (0.5 m/s )
30 LFM (0.15 m/s)
F
5
5
0
20
30
40
500 LFM (2.5 m/s )
400 LFM (2.0 m/s )
300 LFM (1.5 m/s )
200 LFM (1.0 m/s )
100 LFM (0.5 m/s )
30 LFM (0.15 m/s)
10
50
O
10
60
70
80
0
90
20
30
40
50
Ambient Temperature [°C]
Figure 1. Available load current vs. ambient air temperature and
airflow rates for SSQL48T20033 converter mounted vertically
with air flowing from pin 3 to pin 1, TC temperatures ≤ 120 °C,
Vin = 48 V.
70
80
90
Figure 2. Power derating of SSQL48T20033 converter with
baseplate option and 0.5” tall horizontal-fin heatsink.
(Conditions: same as Figure 1)
25
EN
D
25
60
Ambient Temperature [°C]
20
20
15
15
500 LFM (2.5 m/s )
400 LFM (2.0 m/s )
300 LFM (1.5 m/s )
200 LFM (1.0 m/s )
100 LFM (0.5 m/s )
30 LFM (0.15 m/s)
10
5
10
5
0
20
30
40
50
60
70
0
80
Ambient Temperature [°C]
Figure 3. Intentionally left blank for future use.
90
20
30
40
50
60
70
80
90
100
110
Baseplate Temperature [°C]
Figure 4. Power derating of SSQL48T20033 converter with
baseplate option and coldplate cooling. (Conditions: Air velocity
≤ 30LFM (≤ 0.15m/s), Vin = 48 V, TB ≤ 85°C) No thermal derating
required.
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SSQL48T20033
Figure 6. Efficiency vs. load current and ambient temperature for
converter mounted vertically with Vin = 48 V and air flowing
from pin 3 to pin 1 at a rate of 200 LFM (1.0 m/s).
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F
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Figure 5. Efficiency vs. load current and input voltage converter
mounted vertically with air flowing from pin 3 to pin 1 at 300
LFM (1.5 m/s) and TA = 25°C.
FE
11
EN
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Figure 7. Power dissipation vs. load current and input voltage
converter mounted vertically with air flowing from pin 3 to pin 1
at 300 LFM (1.5 m/s) and TA = 25°C.
Figure 9. Turn-on waveform at full rated load current (resistive)
with 10,000 uF output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5V/div.). Bottom trace:
Output voltage (1 V/div.). Time scale: 2 ms/div.
Figure 8. Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM (1.0 m/s).
Figure 10. Turn-on waveform at full rated load current (resistive)
with 10uF tant. + 1uF cer. output capacitor at Vin = 48 V,
triggered via ON/OFF pin. Top trace: ON/OFF signal (5 V/div.).
Bottom trace: Output voltage (1 V/div.). Time scale: 2 ms/div.
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North America
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© 2016 Bel Power Solutions & Protection
BCD.00780_AB
Asia-Pacific
+86 755 298 85888
SSQL48T20033
Figure 12. Output voltage response to load current step change
(10 A – 15 A – 10 A) at Vin = 48 V. Top trace: output voltage
(100 mV/div.) Bottom: load current (5 A/div.). Current slew rate:
1 A/μs. Time scale: 200 μs /div. Co = 470 μF POS + 1μF ceramic
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Figure 11. Output voltage response to load current step change
(10 A – 15 A – 10 A ) at Vin = 48 V. Top trace: output voltage
(100 mV/div.) Bottom: load current (5 A/div.).
Current slew rate: 0.1 A/μs. Time scale: 200 μs /div.
Co = 10 μF tantalum + 1 μF ceramic
FE
12
EN
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Figure 13. Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 μF tantalum + 1 μF
ceramic and Vin = 48 V. Time scale: 2 μs/div.
Figure 15. Input reflected ripple-current, ic (50 mA/div.),
measured at input terminals at full rated load current and
Vin = 48 V. Refer to Fig. J for test setup. Time scale: 1 μs/div.
Figure 14. Input reflected-ripple current, is (10 mA/div.),
measured through 10 μH at the source at full rated load current
and Vin = 48 V. Refer to Fig. J for test setup.
Time scale: 1 μs/div.
Figure 16. Load current (top trace, 20 A/div., 100 ms/div.) into a
10 mΩ short circuit during restart, at Vin = 48 V. Bottom trace
(20 A/div., 10 ms/div.) is an expansion of the on-time portion of
the top trace.
tech.support@psbel.com
SSQL48T20033
13
COMP.
DES.
C1
C2
L1
C4, C5
C3
DESCRIPTION
3 x 1uF, 100V Ceramic
Capacitor
33uF, 100V Electrolytic
Capacitor
F4810 Bel Power Solutions
Input Filter
2200pF Ceramic
Capacitor
Not Assembled
O
F
LI
FE
Figure 17. Typical input EMI filter circuit to attenuate conducted emissions.
EN
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Figure 18. Input conducted emissions measurement (Typ.) of SSQL48T20033.
Conditions: VIN = 48 VDC, IOUT = 20 Amps
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+353 61 225 977
North America
+1 408 785 5200
© 2016 Bel Power Solutions & Protection
BCD.00780_AB
Asia-Pacific
+86 755 298 85888
SSQL48T20033
14
PAD / PIN CONNECTIONS
Pad/Pin #
Function
1.300±0.020 [33.02±0.51]
0.100 [2.54]
0.150 [3.81]
1.100 [27.94]
0.150 [3.81] 4X
ON/OFF
3
Vin (-)
4
Vout (-)
5
SENSE(-)
6
TRIM
7
SENSE(+)
8
Vout (+)
0.900±0.020 [22.86±0.51]
0.300 [7.62] 2X
SIDE VIEW HEAT
SPREADER VERSION
SIDE VIEW
NO HEAT SPREADER
CL
HT (-xAx0x)
PL
Pin Length
±0.005 [±0.13]
A
0.188 [4.78]
B
0.145 [3.68]
Height [HT]
CL
HT (-xAxBx)
F
A
PL
CUSTOMER PCB
Pin
Option
LI
SSQL48T Pinout (Through-hole)
0.375”
[9.5] Max
0.500”+/-0.020
[12.70+/-0.51]
Min
Clearance
[CL]
Special
Features
0.027” [.07]
0
0.027” [.07]
B
CUSTOMER PCB
O
PL
Vin (+)
2
FE
0.600 [15.24]
1
EN
D
SSQL48T Platform Notes
All dimensions are in inches [mm]
Pins 1-3, 5-7 are Ø 0.040” [1.02] with Ø 0.076” [1.93] shoulder
Pins 4 and 8 are Ø 0.062” [1.57] with are Ø 0.096” [2.44] shoulder
Pin Material: Brass Alloy 360
Pin Finish: Tin over Nickel
HEAT SPREADER INTERFACE INFORMATION
tech.support@psbel.com
SSQL48T20033
15
PRODUCT
SERIES
INPUT
VOLTAGE
MOUNTING
SCHEME
RATED
CURRENT
OUTPUT
VOLTAGE
SSQL
48
T
20
033
ON/OFF
LOGIC
MAXIMUM
HEIGHT [HT]
PIN
LENGTH
[PL]
SPECIAL
FEATURES
N
A
B
B
G
0⇒
2250 VDC
isolation
No Suffix
RoHS
lead-solderexemption
compliant
-
A⇒
36-75 V
20
20 ADC
033
3.3 V
N
Negative
P
Positive
Through
hole
0.375”
for -xxx0x
0.520”
for –xxxBx
A 0.188”
B 0.145”
B⇒
Baseplate
option + ‘0’
above
G RoHS
compliant for
all six
substances
FE
Sixteenth
Brick
Format
T
Throughhole
RoHS
The example above describes P/N SSQL48T20033-NAABG: 36-75 V input, through-hole, 20 A @ 3.3 V output, negative ON/OFF logic, maximum
height of 0.52”, 0.188” pin length, 2250 VDC isolation, integral heat spreader (Baseplate) and RoHS compliant for all 6 substances.
EN
D
O
F
LI
Consult factory for availability of other options.
NUCLEAR AND MEDICAL APPLICATIONS - Products are not designed or intended for use as critical components in life support systems,
equipment used in hazardous environments, or nuclear control systems.
TECHNICAL REVISIONS - The appearance of products, including safety agency certifications pictured on labels, may change depending on
the date manufactured. Specifications are subject to change without notice.
Europe, Middle East
+353 61 225 977
North America
+1 408 785 5200
© 2016 Bel Power Solutions & Protection
BCD.00780_AB
Asia-Pacific
+86 755 298 85888
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